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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        function fun(){
            var num = 20;
            var o = {
                stNum:function setNum(newNum){
                    num = newNum;
                },
                gtNum:function setNum(newNum) {
                    return num;
                }

            }
            return o;
        }
        var obj = fun();
        console.log(obj.gtNum());
        obj.stNum(200);
        console.log(obj.gtNum());
        
    </script>
</body>
</html>